Recently, as new solid-state memories, memories utilizing a change in resistance (high resistance and low resistance) of a recording material and called a phase-change memory (phase-change random access memory [PCRAM]) and resistance-change memory (resistance-change random access memory [ReRAM]) are being developed to reach the practical application. The cell array of the above memories can be formed with a cross-point structure having variable resistance elements arranged between interconnection lines and a three-dimensional structure can be formed by laminating the cell arrays. Further, since the chip area can be made small by arranging a peripheral circuit below the cell array, the structure is suitable for large capacity.
As the feature of the cross-point structure, a cell structure having a non-ohmic element serially connected to a variable resistance element is attained since it is of a recording system that reads a resistance change by passing a current and a stray current that flows through an unselected cell at the read time of a selected cell is suppressed. As a result, suppression of a reverse current (prevention of reverse current) in the case of a unipolar operation and suppression of a low electric field leakage current (prevention of a leakage current) in the case of a bipolar operation can be achieved.
However, in this type of solid-state memory, the following problem occurs. That is, as the cells are further laminated, the aspect ratio of the whole cell becomes larger since the thickness of a diode portion is large in the case of pn, pin, Schottky diodes in which the non-ohmic element uses Si as a material and the miniaturization process becomes difficult. In addition, a diode peripheral portion such as a variable resistance element is thermally degraded by repeating activation heat treatment at high temperatures for each layer, problems of reading characteristic, switching characteristic degradation, variation in the resistance change of the cell, an increase in the operation current, an increase in the power consumption and the like occur.